Field of the Invention
The present invention relates to a device for spraying a liquid for use in dye penetration inspection onto a workpiece, in particular a turbine engine part.
Description of the Related Art
Documents EP-B1-1 494 060 and PCT/FR2012/050411 describe devices for searching for and detecting defects in a workpiece by dye penetration inspection and endoscopy.
Dye penetration is a non-destructive technique for inspecting the surface state of a part. The technique is based on the physical phenomenon of capillarity. The workpiece for inspection is covered in a highly wetting liquid referred to as a “penetrant” that penetrates into any defects of the workpiece and that is subsequently removed from the surface by washing the workpiece using at least one emulsifier and water. The workpiece is stoved in order to eliminate the water and then a developer is applied to the workpiece so that the penetrant held captive in the defects becomes visible when the workpiece is examined under ultraviolet light.
In the prior art, the stage of washing the workpiece is performed by immersing the workpiece in vessels containing emulsifier and water, respectively. However, when the workpiece for inspection is of large dimensions, such as for example a turbine engine drum, the vessels have dimensions that are very large. In addition, the weight and the size of the workpiece make that stage relatively complex and lengthy, particularly since the effectiveness of dye penetration inspection depends on well-controlled washing time.
A turbine engine drum comprises a plurality of rotor disks that are connected together and that define inner annular cavities between one another with walls that need to be inspected by dye penetration and that must therefore be washed with emulsifier and water. Unfortunately, those cavities are difficult to access. Totally immersing the workpiece in vessels of emulsifier and water serves to obviate that problem but takes much too much time and leads to relatively large amounts of emulsifier and water being consumed in order to fill the vessels.
There therefore exists a real need for a technology that is capable of processing a workpiece with a liquid for use in dye penetration inspection, such as in particular a turbine engine part of large size being processed with emulsifier and water, and enabling this to be done in a relatively short length of time, e.g. of the order of two minutes, and in a manner that is repeatable and reliable.